Location: Food and Feed Safety Research2009 Annual Report
1a. Objectives (from AD-416)
Design, develop, and evaluate area-wide approaches to aflatoxin elimination using atoxigenic strains of A. flavus. Research characteristics required of processes and equipment for production of inoculum by grower run organizations. Produce inoculum and assess commercial compatibility and efficacy of the area-wide approach.
1b. Approach (from AD-416)
In consultation with Arizona growers and gins, an area-wide aflatoxin elimination program based on atoxigenic strain technologies will be designed and tested. Inoculum production will be scaled up and equipment designed and modified to permit production of sufficient inoculum for evaluation of an area-wide program. Requirements for the different stages of inoculum production will be empirically determined. The economics of atoxigenic strain based programs will be assessed and area-wide influences of atoxigenic strain applications will be quantified.
3. Progress Report
Activities on the project were monitored through meetings, field visits, and site visits to the atoxigenic strain manufacturing facility. The Arizona Cotton Research Protection Council (ACRPC) and Agricultural Research Service (ARS) laboratories coordinate on many activities. Furthermore, the ACRPC Director, made scientific presentations at the Annual Aflatoxin Elimination Workshop. Activities continued during 2009 on manufacture of commercial scale quantities of atoxigenic strains for use in field tests throughout Arizona, California, and Texas. The use of AF36 (strain of the biological control fungus A. flavus) continues to be optimized and characterized through the analysis of fungal communities associated with cotton production in Arizona and on other crops (corn and pistachio) and in other states (California and Texas). Analyses performed in the Quality Control Laboratory and the Assessment Laboratory at the ACRPC-ARS atoxigenic strain manufacturing facility allow improved understanding by growers of the impact of applications. It also provides data for the registration of atoxigenic strains as biopesticides. These strains are grouped according to the ability of the fungal cells of the same group members to fuse and exchange cell material (vegatative compatibility groups). The ACRPC laboratory is currently assessing membership in the vegetative compatibility group of AF36 of around 5,000 isolates during 2009/2010, and also will perform product quality assessments on batches of atoxigenic strain product. The assessment laboratory is also quantifying the extent to which displacement by atoxigenic strain applications is achieved in treatment to 1,000 acres of pistachio and 10,000 acres of cotton within Arizona. The ACRPC/ARS atoxigenic strain manufacturing facility produces atoxigenic strain product for use in Arizona and also for use in large scale commercial tests in California on pistachios (3,000 acres) and in Texas on corn (5,000 acres) in order to permit compliance with the experimental use registrations obtained through U.S. Environmental Protection Agency (EPA). In addition, the facility continues to help ARS to produce useful quantities of experimental formulations. During the summer of 2009, ACRPC initiated with the Tucson ARS location a large scale assessment of fungal community modifications achieved over the past decade of atoxigenic strain use. This will determine the extent of area-wide and long-term benefits achieved with the Arizona cotton-use-pattern. Field personnel of ACRPC are performing the sampling, and the assessment lab is analyzing the resident fungal communities. ACRPC also participated in a study of long-term survival of A. flavus during 2009 in the hope of better describing the life cycle of A. flavus in desert ecosystems.